(1) Field of the Invention
The present patent application relates to boosting the cleaning performance of detergents for washing textiles by incorporating a specific soil-release polymer.
(2) Description of Related Art, Including Information Disclosed Under 37 C.F.R. §§ 1.97 and 1.98
Besides the indispensable ingredients for the washing process such as surfactants and builders, detergents generally comprise further constituents that can be summarized by the term “detergent auxiliaries” and which include different active substances such as the foam regulators, graying inhibitors, bleaching agents, bleach activators and color transfer inhibitors. These types of auxiliaries also include substances that provide soil-releasing properties and which, when present during the wash cycle, support the soil-release capability of the remaining detergent constituents. Analogously, the same is true for cleaning agents for hard surfaces. These types of soil-release substances are often called “soil repellents” due to the fact that they are capable of providing the treated surface, for example of fibers, with soil-repellency. Thus, for example, the soil-repellency of methyl cellulose is known from U.S. Pat. No. 4,136,038. European Patent Application EP 0 213 739 discloses the reduced redeposition when using detergents that comprise a combination of soaps and nonionic surfactant with alkyl hydroxyalkyl celluloses. Treatment agents for textiles which comprise cationic surfactants and nonionic cellulose ethers with HLB values of 3.1 to 3.8 are known from European Patent Application EP 0 213 730. U.S. Pat. No. 4,000,093 discloses detergents that comprise 0.1 wt. % to 3 wt. % alkyl cellulose, hydroxyalkyl cellulose or alkyl hydroxyalkyl cellulose as well as 5 wt. % to 50 wt. % surfactant, wherein the surfactant component consists essentially of C10 to C13 alkyl sulfate and possesses up to 5 wt. % C14 alkyl sulfate and less than 5 wt. % alkyl sulfate with C15 and higher alkyl groups. U.S. Pat. No. 4,174,305 discloses detergents that comprise 0.1 wt. % to 3 wt. % alkyl cellulose, hydroxyalkyl cellulose or alkyl hydroxyalkyl cellulose as well as 5 wt. % to 50 wt. % surfactant, wherein the surfactant component consists essentially of C10 to C12 alkyl sulfate and possesses less than 5 wt. % alkylbenzene sulfonate with C13 and higher alkyl groups. European Patent Application EP 0 634 481 relates to a detergent that comprises alkali percarbonate and one or more nonionic cellulose derivatives. Among the latter, solely hydroxyethyl cellulose, hydroxypropyl cellulose and methyl cellulose as well as—in the examples—methyl hydroxyethyl cellulose Tylose® MH50, hydroxypropyl methyl cellulose Methocel® F4M and hydroxybutyl methyl cellulose are explicitly disclosed. European Patent EP 0 271 312 (P&G) relates to soil-release agents, including cellulose alkyl ethers and cellulose hydroxyalkyl ethers (with DS (degrees of substitution) 1.5 to 2.7 and molecular weights of 2,000 to 100,000) such as methyl cellulose and ethyl cellulose, which are intended to be added with peroxyacid bleaching agents in the weight ratio (based on the active oxygen content of the bleaching agent) 10:1 to 1:10. A detergent in liquid or granular form is known from European Patent EP 0 948 591 B1 and provides fabrics and textiles that are washed therewith fabric appearance benefits such as pill/fuzz reduction, protection against color fading, improved abrasion resistance and/or increased softness, and which comprises 1 to 80 wt. % surfactant, 1 to 80 wt. % organic or inorganic builder, 0.1 to 80 wt. % of a hydrophobically modified nonionic cellulose ether with a molecular weight of 10,000 to 2,000,000, wherein the modification consists in the presence of optionally oligomerized (oligomerization degree up to 20) ethyleneoxy or 2-propenyloxy ether units and of C8-24 alkyl substituents and the alkyl substituents must be present in amounts of 0.1-5 wt. %, based on the cellulose ether material.
Due to their chemical similarity to polyester fibers, particularly effective soil-release agents for fabrics made of this material are copolyesters that comprise dicarboxylic acid units, alkylene glycol units and polyalkylene glycol units. Soil-release copolyesters of the cited art, as well as their use in detergents, have been known for a long time.
Thus, German Offenlegungsschrift DT 16 17 141, for example, describes a washing process involving the use of polyethylene terephthalate-polyoxyethylene glycol copolymers. German Offenlegungsschrift DT 22 00 91 1 relates to detergents that comprise nonionic surfactant and a mixed polymer of polyoxyethylene glycol and polyethylene terephthalate. Acidic finishing agents for fabrics are cited in German Offenlegungsschrift DT 22 53 063 and comprise a copolymer of a dibasic carboxylic acid and an alkylene or cycloalkylene polyglycol as well as optionally an alkylene or cycloalkylene glycol. Polymers of ethylene terephthalate and polyethylene oxide terephthalate, in which the polyethylene glycol units have a molecular weight of 750 to 5,000, and the molar ratio of ethylene terephthalate to polyethylene oxide terephthalate is 50:50 to 90:10, and their use in detergents are described in German Patent DE 28 57 292. According to German Offenlegungsschrift DE 33 24 258, polymers of ethylene terephthalate and polyethylene oxide terephthalate with a molecular weight 15,000 to 50,000, in which the polyethylene glycol units have a molecular weight 1,000 to 10,000 and the molar ratio of ethylene terephthalate to polyethylene oxide terephthalate is 2:1 to 6:1, can be used in detergents. European Patent EP 066 944 relates to fabric finishing agents, which comprise a copolyester of ethylene glycol, polyethylene glycol, aromatic dicarboxylic acids and sulfonated aromatic dicarboxylic acids in defined molar ratios. Methyl or ethyl group end-capped polyesters, containing ethylene and/or propylene terephthalate units and polyethylene oxide terephthalate units and detergents that comprise such a soil-release polymer are known from European Patent EP 0 185 427. European Patent EP 0 241 984 relates to a polyester which, in addition to oxyethylene groups and terephthalic acid units also comprises substituted ethylene units as well as glycerine units. Polyesters are known from EP 0 241 985 which contain, in addition to oxyethylene groups and terephthalic acid units, 1,2-propylene, 1,2-butylene and/or 3-methoxy-1,2-propylene groups as well as glycerine units, and are end-capped with C1 to C4 alkyl groups. European Patent EP 0 253 567 relates to soil-release polymers with a molecular weight of 900 to 9,000 and made of ethylene terephthalate and polyethylene oxide-terephthalate, in which the polyethylene glycol units have a molecular weight of 300 to 3,000 and the molar ratio of ethylene terephthalate to polyethylene oxide terephthalate is 0.6 to 0.95. Polyesters with polypropylene terephthalate units and polyoxyethylene terephthalate units, at least partially end-capped with C1-4 alkyl or acyl groups, are known from European Patent Application EP 0 272 033. European Patent EP 0 274 907 describes soil-release polyesters containing terephthalate end-capped with sulfoethyl groups. According to European Patent Application EP 357 280, soil-release polyesters with terephthalate units, alkylene glycol units and poly-C2-4 glycol units are manufactured by sulfonation of the unsaturated end groups. German Patent Application DE 26 55 551 describes the reaction of such polyesters with polymers that contain isocyanate groups, and the use of polymers manufactured in this way against the redeposition of soil when washing synthetic fibers. Detergents are known from German Patent DE 28 46 984 which comprise as the soil-release polymer a reaction product of a polyester with a prepolymer that contains a terminal isocyanate group and manufactured from a diisocyanate and a hydrophilic nonionic macrodiol.
The majority of the polymers known from this extensive prior art have the disadvantage that they show no or only inadequate activity with fabrics that do not consist or at least do not mainly consist of polyester. Today, however, a great deal of textiles consist of cotton or cotton/polyester mixed fabrics, with the result that there exists a need for more effective soil-release polymers for these types of grease soiled textiles.
It has now been surprisingly found that polymers obtained from quite specific monomers have a very good soil-release action—precisely on cotton-containing textiles.